Transmission gearing for use on driving shafts



J. S. WEARN Aug. 22, 1950 TRANSMISSION GEARING FOR USE ON DRIVING SHAFTSFiled July 9, 1945 HIM 1N E N TO R JAMES. STUART. WE

ATTORN E Patented Aug. 22, 1950 UNITED STATES PAT ENT. FFICBZ;

TRANSMISSION GEARINGFOR USE ON DRIVING SHAFTS James Stuart Wearn,Christchurch, New Zealand,

assignor to Wearns Patents Limited,- Christchurch, New Zealand, acompany of New Zealand,

Application July 9, 1945, Serial No. 603,967 In New Zealand July 12,1944 2 Claims.

This invention relates to reduction gearing for radially with respect tothe axial centre tain the required speed reduction by means of a singlestage belt drive and consequently the introduction of further gearingbecomes necessary.

It is an object of the invention to provide, for mounting upon thedriving shaft, in place of the usual pulley, a reduction unit of noveland simple construction, capable of being inexpensively manufactured,and including a train of gear wheels and a belt drive which latter isarranged to place the belt-tension fairly with the width of the gearwheels,- thereby avoiding any tendency for the unit to be cantedlaterally and so subject the driving shaft to unnecessary strain.

Another object of the invention is to provide a unit of this descriptionincorporating provision whereby the gear ratio between the driving anddriven shafts may be adjusted, thus permitting of the unit beingmanufactured in standard form and readily adapted to the specialrequirements of each purpose to which it may be applied.

A further object is to provide, in a unit of this kind, means whereby itmay be adjusted to set a desired limit to the amount of power capable ofbeing transmitted, so that, in the event of the effort entailed inoperating the driven shaft exceeding such limit, slip will occur,thereby avoiding damage that might otherwise result to the drivenmachine or to the electric motor or other source of power.

With these and other objects in View, the construction includes briefly,a pinion adapted for fixing on the driving shaft, a frame fioatablymounted concentrically with such shaft and in which frame is rotatablymounted a spur-wheel meshing with the said pinion, such spur-wheel beingperipherally grooved through its teeth to provide opposed cone surfacesto receive a belt drive of the V-type connecting with the driven shaft.

The invention further provides for the spurwheel being composed of partseach including a cone. surface and a peripheral series of teeth, suchpartsbeing connected by axially disposed screw means whereby the spacingapart of the said cone surfaces may be varied for the purpose ofadjusting the riding position of the belt drive 2 of the wheel. j

The invention contemplates also the'provision of a liner formed toreceive the said. belt drive, such liner being "interposed between thesaid cone surfaces to be frictionally engaged thereby for the purpose oflimiting the amount of power transmitted to the driven shaft.

In order that the nature of the invention and its construction may beclearly understood, it will now be more fully described and. explainedwith reference to the accompanying drawings, in which: R

Fig. 1 shows, in sectional plan-view, a unit in accordance with theinvention in which provision is made for enabling the cone surfaces tobe adjusted,

Fig. 2 shows, in similar form, a spur-wheel having two pairs ofadjustable cone surfaces,

Fig, 3 shows, also in sectional plan-view, a unit in which the conesurfaces are of a fixed or nonadjustable form and illustrating analternative method of rotatably mounting the spur-wheel for that of thepreceding figures,

Fig. 4 shows, in similar form, a spur-wheel incorporating means forlimiting the amount of Fig. 5 shows, in similar form, a spur-wheelhaving adjustable cone surfaces and illustrating an alternative methodof effecting such adjustment for that shown in the preceding figures.

As here shown, I represents a portion of a driving shaft, such forinstance as that of an electric motor or other source of power. I

Adapted for fixing upon the shaft l, to rotate therewith, is a pinion 2,while fioatably mounted concentrically with such shaft I, to extendradially therefrom, is a frame 3 in which is rotatably mounted aspur-wheel 4.

This mounting of the frame 3 may be accomplished in any appropriatemanner, as for example the pinion 2 may be fixed upon or formed integralwith a sleeve to be received on the shaft I and drivably connectedthereto, as by a key 5, such sleeve providing at either end of thepinion journals 6 rotatable in bearings 1 in the frame 3.

If preferred, in lieu of the plain bearings, so provided, some form ofanti-friction bearings, such as ball-bearings or roller bearings, may beemployed in thus mounting the frame.

The spur-wheel 4 is provided with one or more pulleys each consisting ofan opposed pair of cone surfaces 8 and 9 to receive therebetween anendless belt I0 of the V-type adapted to pass around a pulley on thedriven shaft, such pulley 3 89 being constituted by a peripheral groovedformation of the spur-wheel through the teeth thereof.

The said pulley or pulleys 8-8 will preferably be disposed symmetricallwith respect to the two lateral sides of the spur-wheel 4.

Thus, for example, in the case of a single dismounting the spur-wheeland screwing the composing parts, in the manner already expulley, ashere shown in Figs. 1, 3, 4 and 5, such pulley will b positioned mid-waybetweenthe two sides of the wheel, while a pair of pulleys, asin Fig. 2,will be disposed at .points equidistautlyspaced one from each of suchlateral of the wheel.

The said pulley or pulleys 8-9 may be of fixed or constant diameter andin which case the wheel 4 may be formed in a single piece, as Fig.3.

In a preferred form of the invention, however, such pulley or pulleyswill be adjustable for the purpose of causing the belt to ride at agreater or loss radius from the axial centre of the wheel in order toenable the gear ratio to be adjusted .to operate the driven shaft at ade'sired-spe'ed.

Thus, as shown in l, the wheel is divided into two parts eachincluding-one ofthe cone surifs'ces 8 or 9 and a peripheral series ofgear teeth adapted tomesh with those of the pinion 2.

The two parts, thus constituted, are connected by axially arranged screwconsisting for example of a sleeve 1| having an external screw thread tobe received in correspondingly screw threaded bores in the two parts ofthe wheel, or preferably, as here shown, such sleeve H may be formedintegral with "one -of such parts and screwed into a bore in the otherpart. The pulley will therefore be of the known expanding type, theadjustment being effected by dismounting the wheel and screwing orrotating one of its said parts relative to the other, thereby causingits cone surfaces 8"an'd 9 to approm'h or recede from one another toplace the riding position 'of the belt mat the desired radius from the.axis 'of the wheel and, which being accomplished,

such parts will be retained in their said relation by re meshing theirteeth with those of the .pinion 2.

Similarly, in cases where the spur-wheel is provided with two or morepulleys, as in Fig. 2, such wheel be divided into three or more par-tsinterconnected by screw means.

In cases where it is desired to avoid dismount ing the spur-wheel forthe purpose 'of adjusting the pulley, one portion of such wheel may beformed with a plain or non-threaded bore, as

shown in Fig. 5 to slidably receive the sleeve II l2 place when theadjustment has been made.

Referring now to the modification shown in Fig. 4 designed to provide apulley of fixed or constant diameter with provision for limiting theamount of power transmitted to the driven shaft.

The construction is similar to that of Fig. 1 with the addition of aliner #3 presenting a pair .of opposed cone faces-between which the beltin rides, such liner being interposed between the cone faces 6 and 9 tobe frictionally engaged thereby.

The said liner is capable of axial rotation about the sleeve if and itsouter lateral faces are formed to correspondwith the cone faces 8 and 9;

The arrangement is such therefore that. by

plained, to cause the cone faces 8 and 9 to bear with the requiredpressure against. the lateral sides of the liner, the national st l bi.the latter by such cone faces 8 and 9 may be adjusted as desired.

If preferred, the adjustment of the parts of the spur-wheel to cause thecone faces 8 and 9 to exercise the desired frictional grip upon theliner [3, maybe effected by means of a nut screwed upon the sleeve I] ina manner similar to that shown in Fig. 5.

The mounting of the spur-wheel 4 in the frame 3 may consist of a pin oraxle l4 rotatably received in an axial bore 55 in such wheel, the twoends of such axle being received in holes formed one in each of the twoside members or cheeks of the frame and retained by suitable means, suchfor instance as pins l6 transfixing such axle.

The said mounting will preferably permit of the wheel 4 slidinglengthwise upon the axle 14 within limits provided by the said cheeks ofthe frame, thus enabling the pulley 8-9 to automatically adjust itsalignment with that of the driven shaft.

cases where the spur-wheel is formed in one piece, as in Fig. 3, theremay, if desired, be substituted for the above described method ofrotatably mounting such spur-wheel, a pair of rollers ii rotatablycarried by journals 18 fixed at corresponding points in the cheeks ofthe frame to project inward from the latter with their peripheriesrolling in contact with the inner peripheries of flanges 19 of suchwheel.

In operation, the unit is mounted by affixing the pinion 2 on thedriving shaft, the pulley or pulleys being if necessary adjusted in themanner described and connected with the driven shaft by the belt orbelts it] the tension of which serves to :hold the frame 3 in position.

It will be appreciated therefore that the frame, by swinging to or fromthe driven shaft, will automatically accommodate its position tocompensate for changes in the spacing between the driving and drivenshafts resulting from adjustment of the riding position upon the drivingpulley of a belt of fixed or constant length.

1 claim:

1. Transmission gearing for use on a driving shaft, including a pinionadapted for fixing on of said spur-wheel, said divided parts of thespurwheel being locked in their adjusted nr'asitio'ns b'y meshing theteeth of each spur-wheel part with the teeth of said pinion.

2. Transmission gearing for use on a driving shaft, including a. pinionadapted for fixing on said shaft, a frame ll'oatably mounted about saidshaft, an externally toothed spur-wheel rotatably mounted in said frameand meshing with said pinion, and opposed cone surfaces to receive abelt drive to connect with a driven shaft provided the external teeth ofeach spur-wheel part with 10 2,135,467

the teeth of said pinion.

JAMES STUART WE'ARN.

6 REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 278,821 Reid June 5, 1883 438,250Diescher Oct. 14, 1890 1,952,884 Nichols et al Mar. 27, 1934 Metz Nov.1, 1938 2,144,028 Pilkington Jan. 17, 1939 2,396,860 Lee Mar. 19, 1946

